CVE-2026-64045 (GCVE-0-2026-64045)

Vulnerability from cvelistv5 – Published: 2026-07-19 15:39 – Updated: 2026-07-20 13:42
VLAI
Title
ovpn: tcp - use cached peer pointer in ovpn_tcp_close()
Summary
In the Linux kernel, the following vulnerability has been resolved: ovpn: tcp - use cached peer pointer in ovpn_tcp_close() ovpn_tcp_close() loads the ovpn_socket via rcu_dereference_sk_user_data() under rcu_read_lock(), takes a reference on sock->peer, caches the peer pointer in a local, and drops the read lock. It then passes sock->peer (rather than the cached local) to ovpn_peer_del(), re-dereferencing the ovpn_socket after the RCU read section has ended. Unlike ovpn_tcp_sendmsg(), which uses the same "load under RCU, use after unlock" pattern but is protected by lock_sock() held across the function, ovpn_tcp_close() runs without the socket lock: inet_release() invokes sk_prot->close() without taking lock_sock first. ovpn_socket_release() can therefore complete its kref_put -> detach -> synchronize_rcu -> kfree(sock) sequence concurrently, in the window after ovpn_tcp_close() drops rcu_read_lock() but before it dereferences sock->peer. The synchronize_rcu() in ovpn_socket_release() protects readers that use the dereferenced pointer inside the RCU read section, not those that escape the pointer to a local and use it afterwards. A reproducer follows the pattern of commit 94560267d6c4 ("ovpn: tcp - don't deref NULL sk_socket member after tcp_close()"): trigger a peer removal (keepalive expiration or netlink OVPN_CMD_DEL_PEER) at the same moment userspace closes the TCP fd. That commit fixed the detach-side of the same race window; this one fixes the close-side at a different victim. Tighten the entry block to read sock->peer exactly once into the cached peer local, and route all subsequent uses (the hold check, the ovpn_peer_del() call, and the prot->close() invocation) through that local. sock->peer is only ever written once in ovpn_socket_new() under lock_sock(), before rcu_assign_sk_user_data() publishes the ovpn_socket, and is never reassigned afterwards - but the previous multi-read pattern made that invariant implicit rather than explicit. The same multi-read shape exists in ovpn_tcp_recvmsg(), ovpn_tcp_sendmsg(), ovpn_tcp_data_ready() and ovpn_tcp_write_space(); those will be cleaned up via a dedicated helper in a follow-up net-next series.
Severity
8.4 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 11851cbd60ea1e5abbd97619d69845ead99303d6 , < e5460eb7238c19d651a9b22b2378b587033a4095 (git)
Affected: 11851cbd60ea1e5abbd97619d69845ead99303d6 , < d3ef441907fca7c340979e577a3db3bb634bf166 (git)
Affected: 11851cbd60ea1e5abbd97619d69845ead99303d6 , < 775d8d7ad02aa345e1588424a6a8b9ae49fb9012 (git)
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Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.18.34 , ≤ 6.18.* (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
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              "status": "affected",
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              "versionType": "git"
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              "versionType": "git"
            }
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        },
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          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "lessThanOrEqual": "6.18.*",
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              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.34",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
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                },
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                  "versionEndExcluding": "7.1",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\novpn: tcp - use cached peer pointer in ovpn_tcp_close()\n\novpn_tcp_close() loads the ovpn_socket via rcu_dereference_sk_user_data()\nunder rcu_read_lock(), takes a reference on sock-\u003epeer, caches the peer\npointer in a local, and drops the read lock. It then passes sock-\u003epeer\n(rather than the cached local) to ovpn_peer_del(), re-dereferencing the\novpn_socket after the RCU read section has ended.\n\nUnlike ovpn_tcp_sendmsg(), which uses the same \"load under RCU, use\nafter unlock\" pattern but is protected by lock_sock() held across the\nfunction, ovpn_tcp_close() runs without the socket lock: inet_release()\ninvokes sk_prot-\u003eclose() without taking lock_sock first.\n\novpn_socket_release() can therefore complete its kref_put -\u003e detach -\u003e\nsynchronize_rcu -\u003e kfree(sock) sequence concurrently, in the window\nafter ovpn_tcp_close() drops rcu_read_lock() but before it dereferences\nsock-\u003epeer. The synchronize_rcu() in ovpn_socket_release() protects\nreaders that use the dereferenced pointer inside the RCU read section,\nnot those that escape the pointer to a local and use it afterwards.\n\nA reproducer follows the pattern of commit 94560267d6c4 (\"ovpn: tcp -\ndon\u0027t deref NULL sk_socket member after tcp_close()\"): trigger a peer\nremoval (keepalive expiration or netlink OVPN_CMD_DEL_PEER) at the same\nmoment userspace closes the TCP fd. That commit fixed the detach-side\nof the same race window; this one fixes the close-side at a different\nvictim.\n\nTighten the entry block to read sock-\u003epeer exactly once into the cached\npeer local, and route all subsequent uses (the hold check, the\novpn_peer_del() call, and the prot-\u003eclose() invocation) through that\nlocal. sock-\u003epeer is only ever written once in ovpn_socket_new() under\nlock_sock(), before rcu_assign_sk_user_data() publishes the ovpn_socket,\nand is never reassigned afterwards - but the previous multi-read pattern\nmade that invariant implicit rather than explicit. The same multi-read\nshape exists in ovpn_tcp_recvmsg(), ovpn_tcp_sendmsg(),\novpn_tcp_data_ready() and ovpn_tcp_write_space(); those will be cleaned\nup via a dedicated helper in a follow-up net-next series."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.4,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-20T13:42:45.723Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e5460eb7238c19d651a9b22b2378b587033a4095"
        },
        {
          "url": "https://git.kernel.org/stable/c/d3ef441907fca7c340979e577a3db3bb634bf166"
        },
        {
          "url": "https://git.kernel.org/stable/c/775d8d7ad02aa345e1588424a6a8b9ae49fb9012"
        }
      ],
      "title": "ovpn: tcp - use cached peer pointer in ovpn_tcp_close()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64045",
    "datePublished": "2026-07-19T15:39:30.526Z",
    "dateReserved": "2026-07-19T07:54:57.029Z",
    "dateUpdated": "2026-07-20T13:42:45.723Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-64045",
      "date": "2026-07-21",
      "epss": "0.00156",
      "percentile": "0.05165"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-64045\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-07-19T16:17:44.803\",\"lastModified\":\"2026-07-20T15:17:05.177\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\novpn: tcp - use cached peer pointer in ovpn_tcp_close()\\n\\novpn_tcp_close() loads the ovpn_socket via rcu_dereference_sk_user_data()\\nunder rcu_read_lock(), takes a reference on sock-\u003epeer, caches the peer\\npointer in a local, and drops the read lock. It then passes sock-\u003epeer\\n(rather than the cached local) to ovpn_peer_del(), re-dereferencing the\\novpn_socket after the RCU read section has ended.\\n\\nUnlike ovpn_tcp_sendmsg(), which uses the same \\\"load under RCU, use\\nafter unlock\\\" pattern but is protected by lock_sock() held across the\\nfunction, ovpn_tcp_close() runs without the socket lock: inet_release()\\ninvokes sk_prot-\u003eclose() without taking lock_sock first.\\n\\novpn_socket_release() can therefore complete its kref_put -\u003e detach -\u003e\\nsynchronize_rcu -\u003e kfree(sock) sequence concurrently, in the window\\nafter ovpn_tcp_close() drops rcu_read_lock() but before it dereferences\\nsock-\u003epeer. The synchronize_rcu() in ovpn_socket_release() protects\\nreaders that use the dereferenced pointer inside the RCU read section,\\nnot those that escape the pointer to a local and use it afterwards.\\n\\nA reproducer follows the pattern of commit 94560267d6c4 (\\\"ovpn: tcp -\\ndon\u0027t deref NULL sk_socket member after tcp_close()\\\"): trigger a peer\\nremoval (keepalive expiration or netlink OVPN_CMD_DEL_PEER) at the same\\nmoment userspace closes the TCP fd. That commit fixed the detach-side\\nof the same race window; this one fixes the close-side at a different\\nvictim.\\n\\nTighten the entry block to read sock-\u003epeer exactly once into the cached\\npeer local, and route all subsequent uses (the hold check, the\\novpn_peer_del() call, and the prot-\u003eclose() invocation) through that\\nlocal. sock-\u003epeer is only ever written once in ovpn_socket_new() under\\nlock_sock(), before rcu_assign_sk_user_data() publishes the ovpn_socket,\\nand is never reassigned afterwards - but the previous multi-read pattern\\nmade that invariant implicit rather than explicit. The same multi-read\\nshape exists in ovpn_tcp_recvmsg(), ovpn_tcp_sendmsg(),\\novpn_tcp_data_ready() and ovpn_tcp_write_space(); those will be cleaned\\nup via a dedicated helper in a follow-up net-next series.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/net/ovpn/tcp.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"11851cbd60ea1e5abbd97619d69845ead99303d6\",\"lessThan\":\"e5460eb7238c19d651a9b22b2378b587033a4095\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"11851cbd60ea1e5abbd97619d69845ead99303d6\",\"lessThan\":\"d3ef441907fca7c340979e577a3db3bb634bf166\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"11851cbd60ea1e5abbd97619d69845ead99303d6\",\"lessThan\":\"775d8d7ad02aa345e1588424a6a8b9ae49fb9012\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/net/ovpn/tcp.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.16\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.16\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.34\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0.11\",\"lessThanOrEqual\":\"7.0.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":8.4,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.5,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/775d8d7ad02aa345e1588424a6a8b9ae49fb9012\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d3ef441907fca7c340979e577a3db3bb634bf166\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e5460eb7238c19d651a9b22b2378b587033a4095\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-07-21T09:07:42+00:00",
      "cve": "CVE-2026-64045",
      "id": "CVE-2026-64045",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ovpn: tcp - use cached peer pointer in ovpn_tcp_close()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64045.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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